It is difficult to braze stainless steel in vacuum. Even under the protection of reducing gas, brazing is poor. The main reason is that stainless steel is easily oxidized. Although it is called "stainless steel", in fact, stainless steel is in a vacuum state or under the protection of reducing gas (hydrogen), and a small amount of oxygen will also lead to oxidation of stainless steel and form a passive film.

Even if a layer of nickel is electroplated on the surface of stainless steel, if the coating is too thin, the effect of chromium cannot be avoided. Therefore, no matter which brand of stainless steel is welded, brazing method should be avoided as far as possible, and other methods can be used, such as argon arc welding. If brazing is necessary, it is recommended to plate copper and then nickel before welding. Solder with good fluidity can be used for a long time.